#include <QApplication>
#include <QPushButton>
#include "A.h"
#include "B.h"
#include "C.h"
int main(int argc, char *argv[]) {
    A a;
    B b;
    C c;
    QObject::connect(&a, &A::signalA, &b, &B::signalB);
    QObject::connect(&b, &B::signalB, &c, &C::slotC);

    emit a.signalA();
    return 0;
}
